Preparation Of RhBMP-2 And The Study On Its Promotional Effect On Migration Of MCF-7 Bcreast Cancer Cells

We developed a prokaryotic expression system to produce rhBMP-2 which expressed as inclusion bodies and was renatured by dilution method. rhBMP-2 can be purified by heparin affinity chromatography according to the characteristics of rhBMP-2 with heparin-binding domain.rhBMP-2 was studied on its effect on MCF-7 cell migration. BMP-2 signal in MCF-7 cells and the migration of MCF-7 cells were detected when treated with kinds of concentrations of rhBMP-2 for 24 h, and 30μg/ml of rhBMP-2 was found the best. In order to explore molecular mechanism, we have taken PCR array to screen the expressions of migrating genes of tumor related. Results displayed that expression of Rb1 dramatically increased, and CDH1 (express E-cadherin protein) was the second. In addition, CD44 up-regulation is also very obvious. Since CD44 may be involved in tumor migration process, we further detected the protein levels of Rb1, E-cadherin and CD44 by Western Blotting.Then we detect the distribution and expression levels of BMP-2, Rb1, CD44 and E-cadherin in different tumor specimens by immunohistological staining. It showed that the expression of BMP-2 and CD44 was positive correlating, while the expression of E-cadheirn and Rb1 was negatively correlated to BMP-2, which suggested that Rb1 and CD44 might play a role in the migrating process of MCF-7 cells induced by BMP-2.To study further the role of Rb1 in the migration process induced by rhBMP-2 in MCF-7 breast cancer cells, we transiently transfected MCF-7 with pcDNA3.1(-)-Rb1 plasmids, and qRT-PCR results showed that after transfection, the expression of Rb1 was up-regulated, Vimentin and CD44 were significantly down-regulated.In summary, we found that Rb1 and CD44 might play a role in the rhBMP-2-induced MCF-7 breast cancer cells migration which may occur with the EMT.